This species is characterized by a relatively small habit (leaves, inflroescences, overall plant size), subglobose inflorescences, and linear, relatively short calyx lobes and corollas (for Amphidasya). It is known from a number of collections in a localized area western Ecuador, and is distinctive in the purple-flushed undersides of the leaves. One collection from the Amazonian side of southeastern Ecuador (Croat et al. 91159, MO, Zamora-Chinchipe) appears to represent this same species; the apparently disjunct distribution is notable. 

Amphidasya amethystina is unusual in this genus in its relatively small, petiolate leaves with a distinct blade. It has the characters of this genus, however.